USB: serial: keyspan_pda: refactor write-room handling

Add helper to retrieve the available device transfer-buffer space.

Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

diff --git a/drivers/usb/serial/keyspan_pda.c b/drivers/usb/serial/keyspan_pda.c
index 39ed3ad323651a44888b33330777422bf79c3d81..54a21a99c0018e44b24a2d0acf59cd75ddd4ee08 100644 (file)
--- a/drivers/usb/serial/keyspan_pda.c
+++ b/drivers/usb/serial/keyspan_pda.c
@@ -98,6 +98,42 @@ static const struct usb_device_id id_table_fake_xircom[] = {
 };
 #endif
 
+static int keyspan_pda_get_write_room(struct keyspan_pda_private *priv)
+{
+       struct usb_serial_port *port = priv->port;
+       struct usb_serial *serial = priv->serial;
+       u8 *room;
+       int rc;
+
+       room = kmalloc(1, GFP_KERNEL);
+       if (!room)
+               return -ENOMEM;
+
+       rc = usb_control_msg(serial->dev,
+                            usb_rcvctrlpipe(serial->dev, 0),
+                            6, /* write_room */
+                            USB_TYPE_VENDOR | USB_RECIP_INTERFACE
+                            | USB_DIR_IN,
+                            0, /* value: 0 means "remaining room" */
+                            0, /* index */
+                            room,
+                            1,
+                            2000);
+       if (rc != 1) {
+               if (rc >= 0)
+                       rc = -EIO;
+               dev_dbg(&port->dev, "roomquery failed: %d\n", rc);
+               goto out_free;
+       }
+
+       dev_dbg(&port->dev, "roomquery says %d\n", *room);
+       rc = *room;
+out_free:
+       kfree(room);
+
+       return rc;
+}
+
 static void keyspan_pda_request_unthrottle(struct work_struct *work)
 {
        struct keyspan_pda_private *priv =
@@ -436,7 +472,6 @@ static int keyspan_pda_tiocmset(struct tty_struct *tty,
 static int keyspan_pda_write(struct tty_struct *tty,
        struct usb_serial_port *port, const unsigned char *buf, int count)
 {
-       struct usb_serial *serial = port->serial;
        int request_unthrottle = 0;
        int rc = 0;
        struct keyspan_pda_private *priv;
@@ -479,38 +514,11 @@ static int keyspan_pda_write(struct tty_struct *tty,
           device how much room it really has.  This is done only on
           scheduler time, since usb_control_msg() sleeps. */
        if (count > priv->tx_room && !in_interrupt()) {
-               u8 *room;
-
-               room = kmalloc(1, GFP_KERNEL);
-               if (!room) {
-                       rc = -ENOMEM;
+               rc = keyspan_pda_get_write_room(priv);
+               if (rc < 0)
                        goto exit;
-               }
 
-               rc = usb_control_msg(serial->dev,
-                                    usb_rcvctrlpipe(serial->dev, 0),
-                                    6, /* write_room */
-                                    USB_TYPE_VENDOR | USB_RECIP_INTERFACE
-                                    | USB_DIR_IN,
-                                    0, /* value: 0 means "remaining room" */
-                                    0, /* index */
-                                    room,
-                                    1,
-                                    2000);
-               if (rc > 0) {
-                       dev_dbg(&port->dev, "roomquery says %d\n", *room);
-                       priv->tx_room = *room;
-               }
-               kfree(room);
-               if (rc < 0) {
-                       dev_dbg(&port->dev, "roomquery failed\n");
-                       goto exit;
-               }
-               if (rc == 0) {
-                       dev_dbg(&port->dev, "roomquery returned 0 bytes\n");
-                       rc = -EIO; /* device didn't return any data */
-                       goto exit;
-               }
+               priv->tx_room = rc;
        }
 
        if (count >= priv->tx_room) {
@@ -614,48 +622,27 @@ static void keyspan_pda_dtr_rts(struct usb_serial_port *port, int on)
 static int keyspan_pda_open(struct tty_struct *tty,
                                        struct usb_serial_port *port)
 {
-       struct usb_serial *serial = port->serial;
-       u8 *room;
-       int rc = 0;
-       struct keyspan_pda_private *priv;
+       struct keyspan_pda_private *priv = usb_get_serial_port_data(port);
+       int rc;
 
        /* find out how much room is in the Tx ring */
-       room = kmalloc(1, GFP_KERNEL);
-       if (!room)
-               return -ENOMEM;
+       rc = keyspan_pda_get_write_room(priv);
+       if (rc < 0)
+               return rc;
 
-       rc = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
-                            6, /* write_room */
-                            USB_TYPE_VENDOR | USB_RECIP_INTERFACE
-                            | USB_DIR_IN,
-                            0, /* value */
-                            0, /* index */
-                            room,
-                            1,
-                            2000);
-       if (rc < 0) {
-               dev_dbg(&port->dev, "%s - roomquery failed\n", __func__);
-               goto error;
-       }
-       if (rc == 0) {
-               dev_dbg(&port->dev, "%s - roomquery returned 0 bytes\n", __func__);
-               rc = -EIO;
-               goto error;
-       }
-       priv = usb_get_serial_port_data(port);
-       priv->tx_room = *room;
-       priv->tx_throttled = *room ? 0 : 1;
+       priv->tx_room = rc;
+       priv->tx_throttled = rc ? 0 : 1;
 
        /*Start reading from the device*/
        rc = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
        if (rc) {
                dev_dbg(&port->dev, "%s - usb_submit_urb(read int) failed\n", __func__);
-               goto error;
+               return rc;
        }
-error:
-       kfree(room);
-       return rc;
+
+       return 0;
 }
+
 static void keyspan_pda_close(struct usb_serial_port *port)
 {
        struct keyspan_pda_private *priv = usb_get_serial_port_data(port);